The invention discloses a cleaning method for a high-temperature component. The cleaning method comprises the following steps: first, performing high-temperature rinsing on the high-temperature component; second, performing ultrasonic cleaning on the component which is subjected to the high-temperature rinsing; third, rinsing the component which is subjected to the ultrasonic cleaning in the second step by water; fourth, performing rust prevention treatment on the component which is rinsed by the water in the third step, and then performing conventional high-temperature-resistant paint spraying on the component by using high-temperature-resistant paint. By adopting the cleaning method disclosed by the invention, oil and impurities on the surface of the high-temperature component can be removed thoroughly; the paint spraying quality after the paint is sprayed on the component can be improved remarkably; the integrity and the attractiveness of the appearance are maintained; moreover, the phenomena of discoloring, cracking, bubbling, falling and the like of a paint film are avoided; meanwhile, the high-temperature resistance and the rust prevention performance of the paint film after the paint is sprayed on the component are improved.